Leeks are grown to be used as green onions. They need a site with full sun where they mature in about 130 days. The soil should be well drained and have a pH near 7. Leeks are grown from seed planted 1 inch apart and 3/4 inch deep. The rows are spaced 18 inches apart and 2 inch tall seedlings are thinned to 4 inch spacings. Planting is done from late March to early April. They may be planted in a small bed in the spring then transplanted to 8 inch spacings in June. To blanch leeks, set them in a hole 6 inches deep then pour in some water. The washing action of the water covers the plant with enough soil. If the garden was not given an overall fertilization, use 2 cups of 5-10-10 per 25 feet of row. Apply the fertilizer in a 1 foot band. Keep weeds under control. To blanch, cover with at least 6 inches of soil or fill in the holes if plants are in holes. Blanching enlarges the edible bottom portion of the leek. Leeks need a good moisture supply.
Harvest when plants are at the desired stage. They can be left in the ground or dug and heeled-in in the root cellar.
Failures are due to late planting, poor soil or dryness. Don't allow the growth of leeks to be checked. Storing Leeks
Leeks can be harvested whenever the plants are at the desired stage. They are usually left in the ground for some time, then dug and heeled-in in the root cellar for storage. When kept at a consistent 32 degrees, they will remain good for about one to three months.